Manufacture of white hydraulic cement



rmeui 2a, 1925.

1; STATES PAT N OFHLCE" m IUDSON can; or camronm- F HYDRAULIC idlli'nwing.

W of. hydraulic cement particularly of the Portland type. .'It consists both in novel method of manufacturing a-white hydraulic' cement and in the novel white hydraulic cement as the product of said method, as I shall herein fully describe. My invention is based essentially upon two considerations. One is that iron not anecessary ingredient in the manufacture or composition of a cement of this type. The other is that cording to my method and the materials used it is not necessary to employ an material foreign to the mix, to act as a ux in the burning. As a result of these considerations my invention comprises the use of the mineral labradorite, a triple silicate of lime, sodium and aluminum, of a kind essentially or'approximately free from iron, and white in color, as one of the ingredients of the mix, instead of the usual clay material commonly employed in the manufacture of hydraulic cement; and the use, as the only other ingredient, of a limestone essentially or approximately free from iron. In this specification and claims, for'the sake of brevity, I

shall use the term iron free with res ct to both ingredients, with the understan ing that there maybe and usually is a negligible proportion of iron in both the labradorite Application filed September 4,3923. Serial Ho. 600,935.

anti-limestone, but this does not materially afiect the method or the white product. 40

Incarrying out my invention I mix a proper proportion of. iron-free limestone and iron-free labradorite in finely ground condition, and I sinter this mixture in th'eusual manner pursued in the manufacture of Portland cement. 'I find that the alkali sodium is volatilized in this sintering and passes of? as a fume, while the labradorite before it becomes hot enough to expel its soduim content, acts of itself as a flux to bring into proper intimate contact the ingredients of the mix so that they may chemically react.

Iprefer to use a mixturecontainln'g 7 5 per cent of limestone and 25 per cent of labradorite. These proportions may, however, var withzthe varying chemical analysis of the la radorite and the limestone, but the mix should be such that with the elimination of carbonic acid gas and the sodium oxideof the IIllX, there wlll'remaln calcium oxide,

aluminum oxide and silican oxide in the usual proportion of cement of this type. Bysintering this iron free mixture and pulverizing the resultant clinker, I produce a perfectly white hydraulic cement, which has all the qualities of the usual gray Portland cement.

I claim: 1. The method of making white hydraulic cement, comprising sintering mixture" of iron-free labradorite and iron-free limestone.

2. A white hydraulic cement consisting of the sinter and ground mix of an iron-free limestone and an iron-free labradorite.

In testimony whereof I have signed my name to this specification,

' IRA JUDSON COE. 

